Pion uses industry standard methods for measurement of ionization constants (pKa). We can analyze up to 10 overlapping pKas and can distinguish protogenic counter-ions. Sparingly soluble compounds may be analyzed in mixtures of an organic solvent (such as methanol or DMSO) and the aqueous pKa extrapolated.


Our potentiometric and spectrophotometric methods have measured pKa values as low as 1.0 and as high as 13.0. Using standard potentiometric procedures, we routinely measure pKas between 2.0 and 12.0 for compounds not requiring a cosolvent and between 3.0 and 11.0 for compounds whose aqueous pKa is extrapolated from cosolvent mixtures. If compound structure is appropriate, the spectrophotometric method is applied to measure pKas of water soluble and insoluble compounds between 1.0 and 13.

To submit your compound for analysis:
  • Fill out a Sample Submission Form for each compound.
  • Send a printout with the samples to Pion
  • Please include the Purchase Order number on the sample submission form
  • See the submission form for sample size required.